[PATCH] ASoC: fsl_micfil: Add DC output remover control
Shengjiu Wang
shengjiu.wang at nxp.com
Mon Apr 20 18:53:44 AEST 2026
Add support for the DC output remover feature available on i.MX93 and
newer platforms. This allows users to configure the output DC removal
filter with cut-off frequencies of 20Hz, 13.3Hz, 40Hz, or bypass it
entirely.
The control is exposed as an ALSA mixer control and defaults to bypass
mode. It is only available on platforms with the use_verid flag set
(i.MX93+).
Signed-off-by: Shengjiu Wang <shengjiu.wang at nxp.com>
---
sound/soc/fsl/fsl_micfil.c | 79 ++++++++++++++++++++++++++++++++++++++
sound/soc/fsl/fsl_micfil.h | 1 +
2 files changed, 80 insertions(+)
diff --git a/sound/soc/fsl/fsl_micfil.c b/sound/soc/fsl/fsl_micfil.c
index 2e887f1f1f36..60ac8eabab9d 100644
--- a/sound/soc/fsl/fsl_micfil.c
+++ b/sound/soc/fsl/fsl_micfil.c
@@ -74,6 +74,7 @@ struct fsl_micfil {
int irq[MICFIL_IRQ_LINES];
enum quality quality;
int dc_remover;
+ int dc_out_remover;
int vad_init_mode;
int vad_enabled;
int vad_detected;
@@ -347,6 +348,11 @@ static const char * const micfil_dc_remover_texts[] = {
"Cut-off @152Hz", "Bypass",
};
+static const char * const micfil_dc_out_remover_texts[] = {
+ "Cut-off @20Hz", "Cut-off @13.3Hz",
+ "Cut-off @40Hz", "Bypass",
+};
+
static const struct soc_enum hwvad_enable_enum =
SOC_ENUM_SINGLE_EXT(ARRAY_SIZE(micfil_hwvad_enable),
micfil_hwvad_enable);
@@ -360,6 +366,9 @@ static const struct soc_enum hwvad_hpf_enum =
static const struct soc_enum fsl_micfil_dc_remover_enum =
SOC_ENUM_SINGLE_EXT(ARRAY_SIZE(micfil_dc_remover_texts),
micfil_dc_remover_texts);
+static const struct soc_enum fsl_micfil_dc_out_remover_enum =
+ SOC_ENUM_SINGLE_EXT(ARRAY_SIZE(micfil_dc_out_remover_texts),
+ micfil_dc_out_remover_texts);
static int micfil_put_dc_remover_state(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
@@ -405,6 +414,50 @@ static int micfil_get_dc_remover_state(struct snd_kcontrol *kcontrol,
return 0;
}
+static int micfil_put_dc_out_remover_state(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
+ struct snd_soc_component *comp = snd_kcontrol_chip(kcontrol);
+ struct fsl_micfil *micfil = snd_soc_component_get_drvdata(comp);
+ unsigned int *item = ucontrol->value.enumerated.item;
+ int val = snd_soc_enum_item_to_val(e, item[0]);
+ int i = 0, ret = 0;
+ u32 reg_val = 0;
+
+ if (val < 0 || val > 3)
+ return -EINVAL;
+
+ ret = pm_runtime_resume_and_get(comp->dev);
+ if (ret)
+ return ret;
+
+ micfil->dc_out_remover = val;
+
+ /* Calculate total value for all channels */
+ for (i = 0; i < MICFIL_OUTPUT_CHANNELS; i++)
+ reg_val |= val << MICFIL_DC_CHX_SHIFT(i);
+
+ /* Update DC Remover mode for all channels */
+ ret = snd_soc_component_update_bits(comp, REG_MICFIL_DC_OUT_CTRL,
+ MICFIL_DC_CTRL_CONFIG, reg_val);
+
+ pm_runtime_put_autosuspend(comp->dev);
+
+ return ret;
+}
+
+static int micfil_get_dc_out_remover_state(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_soc_component *comp = snd_kcontrol_chip(kcontrol);
+ struct fsl_micfil *micfil = snd_soc_component_get_drvdata(comp);
+
+ ucontrol->value.enumerated.item[0] = micfil->dc_out_remover;
+
+ return 0;
+}
+
static int hwvad_put_enable(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
@@ -525,6 +578,11 @@ static const struct snd_kcontrol_new fsl_micfil_volume_sx_controls[] = {
MICFIL_OUTGAIN_CHX_SHIFT(7), 0x8, 0xF, gain_tlv),
};
+static const struct snd_kcontrol_new fsl_micfil_dc_out_controls[] = {
+ SOC_ENUM_EXT("MICFIL DC Out Remover Control", fsl_micfil_dc_out_remover_enum,
+ micfil_get_dc_out_remover_state, micfil_put_dc_out_remover_state),
+};
+
static const struct snd_kcontrol_new fsl_micfil_snd_controls[] = {
SOC_ENUM_EXT("MICFIL Quality Select",
fsl_micfil_quality_enum,
@@ -1047,6 +1105,19 @@ static int fsl_micfil_dai_probe(struct snd_soc_dai *cpu_dai)
}
micfil->dc_remover = MICFIL_DC_BYPASS;
+ if (micfil->soc->use_verid) {
+ val = 0;
+ for (i = 0; i < MICFIL_OUTPUT_CHANNELS; i++)
+ val |= MICFIL_DC_BYPASS << MICFIL_DC_CHX_SHIFT(i);
+ ret = regmap_update_bits(micfil->regmap, REG_MICFIL_DC_OUT_CTRL,
+ MICFIL_DC_CTRL_CONFIG, val);
+ if (ret) {
+ dev_err(dev, "failed to set DC OUT Remover mode bits\n");
+ return ret;
+ }
+ micfil->dc_out_remover = MICFIL_DC_BYPASS;
+ }
+
snd_soc_dai_init_dma_data(cpu_dai, NULL,
&micfil->dma_params_rx);
@@ -1071,6 +1142,10 @@ static int fsl_micfil_component_probe(struct snd_soc_component *component)
snd_soc_add_component_controls(component, fsl_micfil_range_controls,
ARRAY_SIZE(fsl_micfil_range_controls));
+ if (micfil->soc->use_verid)
+ snd_soc_add_component_controls(component, fsl_micfil_dc_out_controls,
+ ARRAY_SIZE(fsl_micfil_dc_out_controls));
+
return 0;
}
@@ -1117,6 +1192,7 @@ static const struct reg_default fsl_micfil_reg_defaults[] = {
{REG_MICFIL_DATACH6, 0x00000000},
{REG_MICFIL_DATACH7, 0x00000000},
{REG_MICFIL_DC_CTRL, 0x00000000},
+ {REG_MICFIL_DC_OUT_CTRL, 0x00000000},
{REG_MICFIL_OUT_CTRL, 0x00000000},
{REG_MICFIL_OUT_STAT, 0x00000000},
{REG_MICFIL_VAD0_CTRL1, 0x00000000},
@@ -1143,6 +1219,7 @@ static const struct reg_default fsl_micfil_reg_defaults_v2[] = {
{REG_MICFIL_DATACH6 - 0x4, 0x00000000},
{REG_MICFIL_DATACH7 - 0x4, 0x00000000},
{REG_MICFIL_DC_CTRL, 0x00000000},
+ {REG_MICFIL_DC_OUT_CTRL, 0x00000000},
{REG_MICFIL_OUT_CTRL, 0x00000000},
{REG_MICFIL_OUT_STAT, 0x00000000},
{REG_MICFIL_VAD0_CTRL1, 0x00000000},
@@ -1179,6 +1256,7 @@ static bool fsl_micfil_readable_reg(struct device *dev, unsigned int reg)
case REG_MICFIL_VAD0_NDATA:
case REG_MICFIL_VAD0_ZCD:
return true;
+ case REG_MICFIL_DC_OUT_CTRL:
case REG_MICFIL_FSYNC_CTRL:
case REG_MICFIL_VERID:
case REG_MICFIL_PARAM:
@@ -1210,6 +1288,7 @@ static bool fsl_micfil_writeable_reg(struct device *dev, unsigned int reg)
case REG_MICFIL_VAD0_NCONFIG:
case REG_MICFIL_VAD0_ZCD:
return true;
+ case REG_MICFIL_DC_OUT_CTRL:
case REG_MICFIL_FSYNC_CTRL:
if (micfil->soc->use_verid)
return true;
diff --git a/sound/soc/fsl/fsl_micfil.h b/sound/soc/fsl/fsl_micfil.h
index fdfe4e7125bc..e271c6073f42 100644
--- a/sound/soc/fsl/fsl_micfil.h
+++ b/sound/soc/fsl/fsl_micfil.h
@@ -22,6 +22,7 @@
#define REG_MICFIL_DATACH6 0x3C
#define REG_MICFIL_DATACH7 0x40
#define REG_MICFIL_DC_CTRL 0x64
+#define REG_MICFIL_DC_OUT_CTRL 0x68
#define REG_MICFIL_OUT_CTRL 0x74
#define REG_MICFIL_OUT_STAT 0x7C
#define REG_MICFIL_FSYNC_CTRL 0x80
--
2.34.1
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